Trichoptera (Caddisflies)

Caddisflies are one of the largest orders of aquatic insects. In Tasmania there are around 189 species in 74 genera (Neboiss 2002), with many of these species endemic to the state.   They are closely related to Lepidoptera (butterflies and moths) although their mouthparts are not coiled like the Lepidopterans.  Adult Caddis flies look a lot like moths with hair (rather than scales) covered wings, body and legs, long antennae and large compound eyes.  They live close to fresh water bodies such as rivers, lakes, ponds or swamps. They can also live in saline coastal lakes, streams and rock pools.  During the day the adults of most species hide on vegetation or rocks near the waterways.  They emerge in the evening or at night.

Some species mate in the air, others mate in riverside vegetation or on the ground.  The eggs are laid near water soon after mating.  The larvae look a lot like Lepidopteran caterpillars, but lack the prolegs along the abdomen.   Some larvae are free living and others spin a net  from glands along their body to form a retreat or a portable case.    They have a pair of hooks at the end of their abdomen that can be used to grip to the water body substrate or to hold onto their cases.    The materials attached to the cases depend on the speed of the water that the insects live in. Some attach plant material such as sticks or leaves, others use gravel and small stones.  The tubes protect the larvae from predators.  The larvae feed on plant material.